Grrrr......can't break 60mpg! - Fuel Economy, Hypermiling, EcoModding News and Forum

JQmile · 11-21-2008, 04:05 AM

Ok so I have a 1982 Chevette diesel, rated at 55mpg highway. Until this last week, I got 56mpg without trying too hard. Recently I did a few tests with the grille blocked, tires up, cetane booster in the tank, the windows rolled up, and did a little bit of pulsing and gliding (hard in Los Angeles).....the result? 57.3mpg over 300 miles. Arg! Barley made a difference. Drove 50-55mph too. Might try to get fuel from a different spot and see if that helps. Ideas?

MetroMPG · 11-21-2008, 08:00 AM

Problem is you're now aiming for a target without any kind of feedback to tell you how well you're doing until it's too late (after filling up).

I realize there aren't any simple options for putting instrumentation in your car, but that's the answer, and finding a solution would be my goal if I were in your place.

SVOboy · 11-21-2008, 12:16 PM

Well, it is getting colder, too (even though I was just in LA and I sure wouldn't call it cold).

Try slowing down?

cfg83 · 11-21-2008, 12:20 PM

MetroMPG -

Quote:

Originally Posted by MetroMPG

Problem is you're now aiming for a target without any kind of feedback to tell you how well you're doing until it's too late (after filling up).

I realize there aren't any simple options for putting instrumentation in your car, but that's the answer, and finding a solution would be my goal if I were in your place.

I want to suggest a Vacuum Gauge, but I am guessing that may not be helpful for a Diesel?!?!?!?

CarloSW2

MetroMPG · 11-21-2008, 12:53 PM

While not instantaneous, even very finelycalibrated fuel gauge would help. It might at least permit you to calculate your "tank mpg" daily, rather than waiting for fill up time.

Krousdb pioneered this mod with his Del Sol (pre MPGuino days): he hooked up a digital multimeter (DMM) to his fuel tank's sending unit, measuring resistance I believe. Then he filled the tank a half gallon at a time and charted the results from the DMM as he went.

Assuming you always park in the same place (fuel tank at a consistent attitude), you may be able to get accurate daily/trip MPG readings from this to help you figure out best mods/techniques more quickly.

JQmile · 11-21-2008, 02:00 PM

Hmmm.....good point, I am kind of driving blindly, not like I have a OBD-II port either.....I might screw around with fuel a little (synthetic diesel) when I got the car it was running on jet-a and got 37mpg at 65mph. I switched to regular diesel and it immediately picked up to the low to mid 40mpg range. I also think I might have some drivetrain drag, the car drops speed like a rock from 65mph.

Ryland · 11-23-2008, 12:18 PM

with a vehicle that old I would go over the whole drive train and do a tune up if you have not done this already, change tranny fluid, adjust the injection pump, check wheel alignment, get the narrowest high pressure tires you can find, find out your rim weight and see if there are any newer lighter rims out there, use synthetic oils, foam air filter, larger element oil filter.